The present invention relates to prepaid solutions for mobile roaming and, more particularly, but not exclusively to such solutions that involve the SIM toolkit, that allow text messaging only, and solutions that work in networks that are not enabled with CAMEL.
Today, roaming use of mobile telephones is widespread and subscribers have come to expect that their telephones will work wherever they are located. As long as the user is a postpaid user, that is he uses the telephone and then subsequently receives the bill and pays the charges then the roaming network need merely record the usage and subsequently send the data to the home network which can then bill the subscriber. However prepaid users pay in advance and are only able to use their telephones while their accounts are in credit. This raises a problem with roaming because the roaming network then has to know about the credit status of the prepaid subscriber before it can allow the call, and of course the information is stored at the home network. Thus the default position for roaming prepaid subscribers is to bar them from roaming use.
There are a number of solutions for the roaming prepaid mobile subscribers, that is mobile prepaid users who roam in a foreign mobile network. The most popular solution is based on the CAMEL standard. CAMEL is an acronym of Customised Applications for Mobile networks Enhanced Logic, and is a set of GSM standards designed to work on a GSM core network. They allow an operator to define services over and above standard GSM services. The CAMEL architecture is based on the Intelligent Network (IN) standards, and one of the services most commonly provided is to issue triggers for prepaid roamers which reach the home network and operate the home-network based prepaid system to govern the call. The triggers ensure that the home prepaid system is aware of the call as if it were taking place on the home network and the home prepaid system is therefore able to inform the roaming network whether the prepaid subscriber has credit for the call and when the credit runs out.
Another solution is based on USSD call-back. The prepaid subscriber sends a USSD message to a preset telephone number and a callback is arranged.
Neither of the above solutions is perfect. The CAMEL solution requires that both the home network (HPMN) and the roaming network (visited network—VPMN) support CAMEL and has CAMEL integration in place and a CAMEL roaming agreement between them. CAMEL support costs a fair amount of money for the mobile operator, and not all operators have installed this feature. The USSD solution has a usability issue in that the message has to be dialed in a special way, and not all subscribers are ready or willing to make use thereof. Also certain networks bar USSD messages.
It would be desirable to provide a solution for the roaming prepaid issue, which is
(a) transparent to the end user, i.e. the user is able to dial as usual, and
(b) makes use of the existing CAMEL solution where available, that is if the CAMEL solution is available then CAMEL will be made use of, any new solution coming into action when there is no other option available.
One of the issues in today's roaming mobile market is the complexity of offering subscribers full roaming services. It is possible to offer a complete range of solutions so that subscribers can be provided with the usage they desire from their mobile handsets. However, due to possible exposure to fraud, Operators often wish to limit the usage of their roamers. One of the limits operators seek to place on their subscribers is to bar roaming users from making voice calls.
Now, today's situation is that roamers, once barred from making calls are also automatically barred from sending text messages, such as SMS. However allowing text messaging involves much less exposure to fraud and operators wish to allow text messaging even when calls are barred. However once the telephone is barred, it is barred for all usage.
Prepaid or pay-as-you-go mobile services have created a new business model and service process for operators. Customer loyalty in the prepaid mobile subscriber segment is currently based on cost. Over time, key services such as prepaid roaming may be a more effective means of securing long-term prepaid business.
There is thus a widely recognized need for, and it would be highly advantageous to have, a roaming system which is devoid of the above limitations.